SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1996a368c3b5b4eb1b66b43ec3322e7a01de0277f59cedb939f8564bf6a987b7' 
  AND token = 'SmfGzlP7iEWd0IulLJSFdYFZ0MIa2slt3ee5g7xmv9A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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