SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62cc15348150f75866731ab0f92bf4895378423877d5c83c6f21847e6bd7b0b9' 
  AND token = '1WNxP6tl1mYp+ksLd9NeGxRL8vacq18v/vUpEeqmCtA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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