SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a9f39372f5c33d3b5c2f09fb953b6887f684a316479d6c24caac973f75af5a72' 
  AND token = 'hel0AEhYaubJjwGSD+DgBi1Kh4IPCurb5VSpawlf7wQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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