SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1c5caad1ae7092dc2b035292d1f52d04171ec0f8e8284c20fff94d920d81b2e2' 
  AND token = 'XyDvvvuo0be5ulE+MtpDyBHk/vo8vN3pnPxnEAh5r80=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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