SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eba4f3c31228d48819990d94694a5ac243341e370471e40116963a03cb39b324' 
  AND token = 'TXA5unoicT3pDPuR5a5QFuogMz6eqUagsCQrNidOsY8=' 
  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"
    }
  }
}