SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c88f660147f6a03738c15a5723b9d23ba1978ff77bd61ce35e7ce5ffd8273a2d' 
  AND token = '+izJYkYdSxSj93s167ynosUS1GlXxJ2kiMG0lRs9PwE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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