SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1ede66c928198a3a1b3d3e9f3b0745433cd985197857a4ead373c8197d0d74b1' 
  AND token = 'j5milwRjvJDv/5Uf8xdQFRekrEN5AIpVx4zLiTjv+Q8=' 
  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"
    }
  }
}