SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8b19804b69225c45dc77652b4a60dc287b2e07f113291f8b22c1e21ea1734a18' 
  AND token = 'VEt98WLDlO8A09iQXMt9BC1UBugktLYPiD6PG+47OYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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