SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f246b5d8c4fcf53a362ceac3aaebe1cdb790538ebb49b6d1faa2ae6a01505cee' 
  AND token = 'TAysFjHWLLqstECNAJfGojiq5fCUxPg4ShbDCMElwuM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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