SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aa2fb4ffe16955cf6180d971f5bb1d53199062475f832631a751b5565c6cad2c' 
  AND token = 'YL5uSYnG/miQTV5AR3sGKjyPaRtPDEQyIX2iq/vjvGg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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