SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86e7e9847097bc4ca954d61c48f357f118f3bea135c786f29714da953e1264a2' 
  AND token = 'SbFNQFQUNg4fBZBoeJVt3bCDzMAcJUJvfokEGWWYCEU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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