SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '944f2231cd3b2be52185bf5918453c46ddf5f221a4798d22ca54de8b88b47da3' 
  AND token = 'B4w4gb5u+N1qw26ssnmvu8e7HCO2pE5bk+hVNuVIOlk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}