SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aefbdc1bf43f978f952a05b9f3a159a834525e0713678359af44c19de2e04471' 
  AND token = 'WGZlP6+jtwJ7ualMPtYShzd5OCfKczSCARONIGWnI5Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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