SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '747dc2b77b0f07bf50bfd36c3834007cd1dea0662683bfd66d7509e22f44ce89' 
  AND token = 'ieT85mz0TmcJaw1haere2wTCcV/JexTlEv6zEfCiiBA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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