Sandbox

SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0cd9ce29b99f686f710e1a2446df8d103312532298cf5d1250ecf59d9c715bb' 
  AND token = 'kV5ZzaxZjiLtUyqrb6Q7ObOuHlqZ+kEBws7cyM7EiyA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}