SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6c49a4d43e344027e2194935bfa988900533869783e2381655d6ed3d63515fc1' 
  AND token = 'ckAEW+HayXqDFDhFRKHwap7xqjI8yn8y89xhljTOWA0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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