SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '904fb4d3f4e13028ac1cffa2ab6580372ad87a2cc12df295a539f47233eac38a' 
  AND token = 'mMWG9hBxK7EA/IWO32TUdu+AkmYecPWLOY6r3isPEXI=' 
  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"
    }
  }
}