SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '48a120a84f997bb5a7d0776a6be04fb6f03b8c9f9eada6cd3391da345b5191f0' 
  AND token = 'nKNm8jKS5RbzZThX5SQBTahZqBZ/Wng8WNgDrn3SQlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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