SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '185ef0edd722bc244165377ef603c8030051a3dce0f632230659389964b0d878' 
  AND token = 'CL+9UnkdCNR+wIPvgl+0wgV+o4EhFTsDsR6X+4zBc5E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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