SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8836bb8cb329bf4b900608450acd1aeb7d2baea519e629412d7ac77344b07bf4' 
  AND token = '4uqOAwkIKdq86NJpxGuFeuc159wz0d+6StWXj4xnygA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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