SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ff5975e6cce11f31551096eec6c5ef068a84e44863916e593305b00dc00ceca4' 
  AND token = 'j54jwaPhFbUEbN7QEtsAzESraWqxGc6K0CEiSr1aqJM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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