SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c39ac7edb5fa46b04127d43492b5f7c441d2cb707ef1cbd6b3666d38ce6cbbcc' 
  AND token = 'FkNa5myYxXU74PtwCL1LHMgPWrKYJ7f/cZ8UzBnQGqo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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