SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ca2dab1504c4189e102870e0594070d4035f35b76d2907c8865d3e6b9655d212' 
  AND token = 'TwTg1RvSuhiD+zFx4cGVJn0wdpggEMreNtMHp4G5qKU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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