SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c87f56047b2507fd57df8c92a072358b5cad6cda2c49acff3da5673315f5eb69' 
  AND token = 'HgJaKNyHlQLo2+/vw3+/0qha4VvcAF2VKw0L/2G1KxI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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