SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a4cbd055b0c4e22fd988cd7d93d98a122174e51be7c3c34f2c9f3f508601381' 
  AND token = 'KVwgOJXJkxtvUz9cSZCiU+MRQomasPDqE8Csk1lFK3Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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