SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ffd48025f712397ae05800045dbd512707938bbf9f0d556987f0dd1ef2b487b4' 
  AND token = 'BhOfOxO5ee9j5vsOh/LUe7dSL+PHWDWCE/4StBectrA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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