SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'd7a1a492dcb817e4acf1eb89824240dd5a1811270ed29345b546a7b00263f0a8' 
  AND token = 'bpbkvZKV6CETrWEpTRLW2QuZRhCSUK2LA+GGMNNwY0o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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