SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'abc709f9045b2f39f1786d8226a8d4bb6fab437092dec8e9c059a886277c7591' 
  AND token = 'axDVvHVu0ff+ZBHf8LLFqPASGB7PLz02nU/Aipw2Yec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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