SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3cd926c85a236a46227e35a28fa66e9a481b6ff0d0a1281336f311092fba0714' 
  AND token = '1CcXqThGYLj8DkLjKYUXwO2WkVUWaXWvag/DUB13X5A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}