SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1eec1109e4785c2fa7832f12653bd0c60593e16a571dd296034cdddac01957d' 
  AND token = '2ITBqMf/sow1Glh70tA+fq8YI5wYKabZGxbtrni0b0k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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