SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9a28ce1cd4e90024dd5164ee950d8f0847e75c87e4f9e3e211fa60fd80a3bf86' 
  AND token = 'jmnkpu22KImSnUfSzXbJjTeXINIWoWvjnK/WPPGNRGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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