SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ceef031830aba1e6287c8a3b895a1da3052e42dce5f313a2272032c3457f0329' 
  AND token = 'YzEh7MIip/R0GH++g8+FVXJzpB0AHoWnh+zfmCYwsRQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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