SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '471153997b54f374a0abda6eadf78020bfad98b2aba0cffafecd18b4b1d2d25d' 
  AND token = '5mXtqYoP6wtXfXVyYkQVqNtQXy0UwQX7682uUFL0spM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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