SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f37d796a331f0a4545ba589cfeceb7c3b4f7930ff88aad56f957fcb6c9b4f2f5' 
  AND token = 'Qdo+BRYKtf9441I2iBpg2pci1eZ7icH+FXUPxNdnXgA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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