SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6898d4e2cfcf549b06f6930c4bdc68cdc10baafb1aae60603a5458bda9f78ea' 
  AND token = 'cLBK5dC31yMKMvSX0TA/RwlGwALsUFJoVQU8YZZrB+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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