SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dd7b4284495f44b5c410569c2608a2784b0fcc2eee1feba8f8f4f5a0f33e9147' 
  AND token = 'C/ZwassC9C1dnEs7NrVGpZvw2o8ZsqMsml7mmMhHIq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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