SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e343f28cc1b3cd02ec2f26d59e53a3871a7c8ffe295159dbcfe055a1de1f096' 
  AND token = 'n2hWJLy3SzLCByNahbdcyPBmhGFi9pFax/OyzNBXg4I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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