SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a036d4df04236d3e1d146e7acd8affd07cd0cf0037090d34c260949580cccf43' 
  AND token = 'CpR3TDEXvvh9qC18D1Bm5hasNjwhfqoCzssovcvXSjM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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