SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2eb7fdbad7dd9ecbe907893c51487d2b3b0c27719a0cba539d9385c21cad0c4d' 
  AND token = 'Na/T/JX5Aow+Yv0DTYSTseSm4o7RKK7I/Ck2R4qiU7k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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