SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d95e444818fe389c33ea749860a433c74a8037b6a5ffc872cad936233bfce8' 
  AND token = 'YI+ZUR1g7pCKTHneiYSTTNsFuuI8aUgai+U1HDz53Tw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00049

JSON explain

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