SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9ee963e9040cc0cb10710d21a2868e13734676117fd871a3f1c65eea15717fbd' 
  AND token = 'DuT6ZR3Ien5ul793KRXhoEbp3SjylM40dpU6XjrQo14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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