SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aac55c7ecf62c34946e395c52e97b55c75aa07120ac2200d61dfe127f35dd10a' 
  AND token = '2h/RpZ05cmEasBXdH0fkEvYRReNTQLMlazEcq6MKuGs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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