SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '3c9162eb8fb4511c3e56a83e81590b61cc50bb6213f127fe1ef11a6209f4ce3a' 
  AND token = '9N/S8/aYVpkyNisVMtWMtXgvezq3iy/iEA46V9ErPho=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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