SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'f8a3e55cb6fd85e22665d1bbcee660d74e1c777580a3e03d95165b0666cbeb4e' 
  AND token = 'bKHTxMMg+OK+kt65ak3ugudJquqcxngM6FfsOqd4Wlo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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