SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f8a2bb74681ab14198d4b358d2b6c65c1a13de32e82aa039d2d6df940b930b94' 
  AND token = 'ZGnK1lqy5MFwfEIpxVM+ohvOcBdK/JW8lD2VK+DvEVU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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