SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bbe032cd0a49bcfe0a5e1175e87f96457b3ec05dd0fb22ab5b0dbb2a19bd072' 
  AND token = 'rfDCcEXg6gaJWU0cOTsiaELNQKKSXGbneM0AWa9Ts+8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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