SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5bfd24416009a643d6a98367e6bb7c5b27e7c5f413ef04b1dc713d6c4c0a9f76' 
  AND token = 'VkIRfULPNOYWtg/wvvJ3N5MLcnpEQujfKRu+/p6qwCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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