SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '97071e87c6ec1aa64075b12c8c6155588d100c9141adfa881e375ca7f771226c' 
  AND token = 'VfagEtpTiCm+7WCsUunN6yYOqHLuU4WbNKQe2iNrIO8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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