SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59396aba89c51ffe3ed13cdacfb0569a52dde8a3cf42502f8f615fd5189e91ed' 
  AND token = 'I7i5h3TPqen0zWskt4ysZXHX/2jAnLyEhI9lu0ibZi8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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