SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b90d2550761eacf651e6555052e49cd1300b81ea09a10a7ab7ae6dc281aa43c6' 
  AND token = 'Bh2HXJBtCmjRc8pGB8tSIc+XdwkbmENGmXNCNpBw9cQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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