SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '50f3fa137de9dbaa52a5ebb8b85497a18c80998559669a8b896e3ba43dc0d3bf' 
  AND token = 'SHNdE8bzLHFarOOlo8n29iJPDwP9CPd316GCca2rH4Y=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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