SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88af0a287f519b527c02926420f6c0905476a3551740f016d4561beae39bf011' 
  AND token = 'DsiF+z2XUIqy5ksv4nPQlDTfmVmT9EnT1iI3drmlcsY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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