SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b5cacba89b1ae414f340adaf4363bbfb92a6c1accf84cf1c7bba5f7e1f59cbb1' 
  AND token = 'G6SbwFDuVCPZYxbIB82666caYxVfdzYzcFgItNf+Ee0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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