SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4e755f2dadd588be3719c7f73ba6c081939401bd7b52063f653f572bf9f26c8a' 
  AND token = 'sbaMUyRq4JE111vZ1DKMuuxJSh/ynQP4paTFB6KWMF8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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