SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd06af8b38be848ec652a998e816028bd3508eb82e83c968321114f891cb38547' 
  AND token = 'qfp4ln0su0dC50CWrSZENI1MZLfCccfrBqPE0wDcpJ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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