SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a0f7da4a48b9cb9910f3628b7724f2919415657c775f00de36f5c26422c8bf71' 
  AND token = 'SmllDZpAqORK8uBUi+uN1B1nLdpuhS4tYHTzdgohuQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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