SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a15d5948b9730a1abb50a2e4735aa758dccfb180c1a40916df63d9458e7a959' 
  AND token = '6wJigmOjq7v+eLAuJCA/NwInMHPhCqwTb9DX5lJ1+iU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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