SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6679536d19770a6b469e30b64330d56cc59dd39a9f5264e4d7977e1550ce7d30' 
  AND token = '051n4gqAa63Ok8Mutr/rFJwGdfzPi9AgG3gqxYRnMxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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