SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e664501369bfb576c5ab2a017d722482cdaa0bfb29433e819139208fe7430d98' 
  AND token = 'XwwOPUK972q3PyMPUY8pQGKtk97pL/AVjg+ntttU82g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

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