SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'add64cbeb232eab37d4d2801257bede0fcf174af83d8e5b19eab53d53f0db59b' 
  AND token = '62ILCPBlwkECFPduavrlDm+OLW3PuEi0nnUAS6rEH/k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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