SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36aed7067b925268feda7a5f8fc254190eab4304c2d2f665499d0d730843bf21' 
  AND token = 'PhBBQ8Rpa3MjKn12tEI4P+EoNXH6r1Uj+/vmyskLUrY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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