SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bcebd07cb0e0623765af93ccd0a014ba280c300a0776911e2e379980fbe8cd10' 
  AND token = 'uN86sBK89XmC57qjlyu8j5ihuwq84qGfRHmx8ComVGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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