SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62f431a1c1844e3e4259fee2fac0e797608647e894e5740b1ee63ba42255f247' 
  AND token = 'j8zzEpbmW7RTypBtenwvLqaeAb2NUO5Z59qAVGuxkJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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