SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e120f80687692e13f09c25d5f136ef2dd8eb2215f73fe708f6e81b39b6ae2d3d' 
  AND token = 'rdm1JmxplWNGMkh5K6Nnv4j7jU4lHqPYalRqbgrlUgY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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