SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b4dc14c17707eb96908a82def463503a2c918405968eb009d65213507862625' 
  AND token = 'HMV7pLTPn94NgFPEkOXLEOnL0uWjfbVwfSH+roRGQag=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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