SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '527bab3d77ca570f18f0454bda27febfc6a1d3343915b3ed6e1a561963bfea1e' 
  AND token = 'uL+vTm+oGWw7AeFzJy3/FjhIrT2YEY1uJ4dBMdqsEcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}