SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '08ae885c0e350725c63bfa0d4162d1796738c0373999a17a4081db8f0a86a9fe' 
  AND token = 'xLpfvlKQpH/JUa0fj93gCDv3r76haEXQxFTUlcGEpWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}