SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87c16a38f4630165975998425713c7f5272e494f799db39d454f419b32e8bbda' 
  AND token = 'hnahw2eVrbFH2QDJpBc5aQVBx0zDKUH/gg/cYpd79XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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